#ifndef IO_HH
#define IO_HH
#include <iostream>
#include <string>
//Provides input validation for numbers, strings, and choices.
//Handling input and output.And check whether it's correct input.
//Not class because no object and attributes.
using namespace std;
namespace IO{
    int getNumber();
    double getAmount();
    std::string getString();
    bool getYesOrNo();
}
#endif